Home water purification system with filter end of life monitor

ABSTRACT

A point of use water purification system for home use is provided comprising a carbon block filter housed in a self-contained disposable pressure vessel for removing particulates and organic contaminants from water. The filter is provided with a pore-size distribution, a binder and a flow path which optimizes filtration performance and enhances microbiological kill rates obtained in a source of radiant energy which is used to kill microorganisms in the filtered water. The source of radiant energy comprises an ultraviolet discharge lamp having an elongate central axis and a diverter for providing a spiral plug flow of water about the discharge lamp. A flow regulator adjusts flow through the system for varying line pressure conditions to ensure adequate exposure of microorganisms to ultraviolet energy. A lamp control circuit conserves power and optimizes ultraviolet output. A diagnostic system includes a filter monitor which provides an automatic indication to the user when the filter has reached its end of life. The diagnostic system includes a radiation source monitor which provides an automatic indication to the user when the UV discharge bulb has malfunctioned. A filter quick-disconnect, a radiation source quick-disconnect and associated power safety interlocks protect the user and facilitate the safe and easy replacement of the disposable filter cartridge and ultraviolet discharge bulb.

This is a continuation of application Ser. No. 08/479,430, filed Jun. 7,1995, now pending; which is a divisional of application Ser. No.08/035,011, filed Mar. 22, 1993, now U.S. Pat. No. 5,536,395.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to home water purificationsystems and, more particularly, to a high performance, self-contained,point of use water purification unit that features a replaceableactivated carbon filter, a replaceable ultraviolet radiation source anda diagnostic system that signals when the unit requires maintenance.

The following related patent applications are directed to differentaspects of the water treatment system of the present application. FAUCETDIVERTER VALVE, Ser. No. 07/977,161, filed Nov. 16, 1992, now U.S. Pat.No. 5,279,329, issued Jan. 18, 1994. Ornamental design for FAUCETDIVERTER VALVE, Ser. No. 07/930,182, filed Aug. 17, 1992, now U.S. Pat.No. Des. 348,722, issued Jul. 12, 1994. WATER TREATMENT SYSTEM BULBSTATUS MONITOR CIRCUIT, Ser. No. 08/002,820, filed Jan. 6, 1993, nowU.S. Pat. No. 5,401,394, issued Mar. 21, 1995. UV BULB INTENSITY CONTROLFOR WATER TREATMENT SYSTEM, Ser. No. 08/016,594, filed Feb. 11, 1993,now U.S. Pat. No. 5,324,423, issued Jun. 28, 1994. ULTRAVIOLET LAMPASSEMBLY FOR WATER PURIFICATION, Ser. No. 08/016,140, filed Feb. 10,1993, now U.S. Pat. No. 5,393,419, issued Feb. 28, 1995. WATER FILTERCARTRIDGE, Ser. No. 08/017,773, filed Feb. 16, 1993, now U.S. Pat. No.5,344,558, issued Sep. 6, 1994. Ornamental design for WATER PURIFIER,Ser. No. 07/931,288, filed Aug. 17, 1992, now U.S. Pat. No. Des.355,700, issued Feb. 21, 1995.

2. Description of the Related Art

In the industrial arts, it is known to use an activated charcoal filterin combination with a radiation source to filter and purify water. Forexample, such systems are used in the production of bottled water. Theadaptation of this technology to home use has been difficult. Industrialsystems are large, expensive and require special knowledge and tools tomaintain. The expense of these systems is often due to the fact thatthey are designed to process water volumes many times larger than thoserequired for home use. Other challenges encountered when designing sucha water treatment system for home use stem from the varying operatingconditions in each home. For example, water quality, water linepressure, water demand and the sophistication of the user will vary indifferent homes.

Some water purifiers intended for home use are known which combineactivated carbon filters with an ultraviolet (UV) radiation source.However, these home units have had a limited success due to inherentproblems with their design that make maintenance of the units by thehomeowner difficult and inconvenient. This can result in a waterpurification unit that, in time, operates only marginally if at all.Where the water purification unit is being used with a source ofdrinking water that contains contaminants or microbiological activity,this lack of maintenance can have serious consequences.

The effectiveness of radiation in the killing of microorganisms isdependent on a number of factors. One important factor is the status ofthe source of radiant energy. For example, the performance of most knownultraviolet discharge bulb designs degrades with time. It is thereforedesirable to monitor the radiant energy source and alert the user ifthere is a malfunction. Some artisans have provided a removable housingcover for inspecting wiring and other electrical connections, yet havenot provided a safe and convenient way of removing the radiation sourcewithout first removing an array of electrical connections and/orstructural members. Thus, it is desirable to provide a substantiallyself-contained radiant energy source which is easy and safe to replacewhen there is a malfunction.

Another factor that is important in the kill rate of microorganisms isthe performance of the carbon filter which removes contaminants from thewater prior to irradiation. The effectiveness of radiation in thekilling of microorganisms is dependent on the clarity of the water. Ifany significant particulate contamination defeats the carbon filter,such contamination can mask or protect the microorganisms from killingradiation. Thus, filter design should be optimized to provide thehighest quality water for the irradiation.

All filters have a limited useful lifespan after which contaminantsbreak through the filter. Since the kill rate of the radiation isdependent on the performance of the filter, it is desirable to provide afilter monitor to alert the user when the filter has reached the end ofits useful life. While prior artisans have provided techniques foropening a pressure vessel containing a carbon filter used in prior artwater purification systems of this type, such techniques are cumbersomeand somewhat burdensome for the user because water connections must beremoved and a seal broken on the pressure vessel. Further, the user isrequired to handle a wet filter body covered with contaminants. Thus, itis desirable to provide a substantially self-contained filter cartridgewhich requires a minimum effort to replace when the filter monitorindicates that the filter has reached its end of life.

SUMMARY OF THE INVENTION

According to the present invention, these and other limitations in theprior art are overcome by the provision of a point of use waterpurification system for home use comprising a carbon block filter housedin a self-contained disposable pressure vessel for removing particulatesand organic contaminants from water. The carbon filter is provided witha pore-size distribution, a polymeric binder and a radially inward flowpath which optimizes filtration performance, provides ample water flowand maximizes water quality for enhancing microbiological kill rates. Asource of radiant energy is provided for receiving filtered water andkilling microorganisms. The source of radiant energy comprises adisposable ultraviolet discharge lamp or bulb having an elongate centralaxis. A diverter is provided to establish a plug flow of water about thedischarge lamp for maximizing the exposure of microorganisms toultraviolet energy and enhancing microbiological kill rates. A flowregulator is provided for regulating the flow of water through the watertreatment system under varying line pressure conditions to reduce stresson the system, to ensure adequate exposure time of microorganisms toultraviolet energy and enhance microbiological kill rates. A filtermonitor is provided for monitoring the amount of water flowing throughthe filter and providing an indication to the user when the filter hasreached its end of life. A filter quick-disconnect is provided for theuser to quickly and easily change the self-contained filter or filtercartridge in response to an indication from the filter monitor. Aradiant energy monitor is provided for monitoring the performance of theultraviolet discharge bulb and providing the user with an indicationwhen the UV bulb has reached its end of life. A radiant energy sourcequick-disconnect is provided for the user to change the UV dischargebulb in response to a signal from the radiant energy monitor that thedischarge bulb has malfunctioned. The source quick-disconnect works incombination with an interlock for automatically disconnecting power tothe system so the user can safely and easily change the UV bulb. Thelifespan and performance of the UV discharge bulb is enhanced byproviding a power supply circuit which automatically lowers electricalpower to the UV bulb in the absence of a flow signal from the filtermonitor indicating when the user is drawing water from the watertreatment system, thus conserving electrical energy, preventingunnecessary heating of the water treatment system and the watercontained therein, increasing the efficiency of the ultraviolet bulbwhen water is drawn from the system and maximizing microbiological killrates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the water treatment system unit of thepresent invention installed at the point of use, namely, a kitchencountertop adjacent a kitchen sink;

FIG. 2 is a partial elevation view partially in section of the watertreatment system;

FIG. 3 is a partial exploded assembly of the water treatment system;

FIG. 4 is an exploded assembly of a base, shroud and hinge of the watertreatment system;

FIG. 5 is a top side perspective view of the water treatment system;

FIG. 6 is a bottom side perspective view of the water treatment systemwith an exploded assembly of an inlet and outlet water connection;

FIG. 7 is an exploded assembly of the base, a main circuit board and asource pressure vessel of the water treatment system;

FIG. 8 is an exploded assembly of the source pressure vessel and a flowswitch of the water treatment system;

FIG. 9 is an exploded assembly of the base and main circuit board of thewater treatment system unit;

FIG. 10 is a partial side view of the base of the water treatment systemunit illustrating a plurality of tangs which engage the filtercartridge;

FIG. 11 is a partial side view in section of the filter cartridge;

FIG. 12 is a partial side perspective view partially in section of thefilter cartridge;

FIG. 13 is an elevation view partially in section of a radiation sourceof the water treatment system;

FIG. 14 is a perspective view of a diverter used to establish plug flowin the radiation source of the water treatment unit;

FIG. 15 is a cross section of a flow regulator in the water treatmentsystem;

FIG. 16 is a schematic illustrating a UV bulb intensity control circuitfor the water treatment system;

FIG. 17 is a schematic illustrating a UV bulb status monitor circuit forthe water treatment system; and

FIG. 18 is a schematic of a microprocessor and flow switch whichcomprises a filter cartridge status monitor and which drives the audioand visual diagnostic output.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference now to the figures, and in particular to FIG. 1, thepoint of use water treatment or purification system of the presentinvention is illustrated at 10. The water treatment system of thepresent invention is a so-called point of use water treatment systembecause it is designed for use in the home at the point where water isdrawn for cooking and drinking purposes. For example, the watertreatment system unit 10 is illustrated in FIG. 1 on top of a kitchencountertop 11 adjacent a sink 12 and a water faucet 14. The watertreatment system 10 is connected to the outlet of the water faucet 14 bya diverter valve 15 and a pair of flexible tubular conduits 16. Thewater treatment system 10 is normally connected to a convenient sourceof electrical power such as the electrical outlet at 18.

With reference now to the remaining figures, and in particular to FIG.2, it is illustrated that the water treatment system 10 comprises afilter 20 for removing contaminants from water and a source of radiantenergy 21 for killing any microorganisms that pass through the waterfilter 20. As hereinafter described, the filter 20 comprises a pressedcarbon block filter having a specific pore-size distribution, binder andradially inward flow path which enhances the performance of the radiantenergy source 21. As hereinafter described, the radiant energy source 21comprises an ultraviolet discharge bulb or lamp for irradiating waterwhich is passed around the bulb and killing any microorganisms containedin the water to purify the same. The filter 20 and UV discharge bulb 21of the water treatment system 10 are disposed on a base 22 which iscovered by a shroud or cover 24. In the present embodiment, the base andshroud are formed from a polymeric material and a plurality of legs 25are molded into the bottom of the base 22 for engaging the surface ofthe countertop 11 illustrated in FIG. 1. The base 22 and shroud 24 arebetter illustrated in several of the other drawings including, forexample, FIGS. 3, 4, 5 and 6.

As hereinafter described, the water treatment system unit 10 furtherincludes a filter monitor circuit for providing a measure of theaccumulated amount of water flowing through the filter 20 and providingan indication of when the filter has reached its end of life. Withreference again to FIG. 2, the filter 20 is housed within a disposablepressure vessel or filter cartridge 28 which includes a filterquick-disconnect or bayonet coupling at 30 for providing the user withthe ability to quickly and safely change the filter in response to anindication from the filter monitor. The filter monitor provides a visualand/or audio signal to the user when the filter has reached the end ofits useful lifespan. An audio enunciator is disposed within the base 22and the base contains a light emitting diode (LED) display at 31 (FIGS.1, 3 and 5). The filter cartridge is provided as a self-contained,preassembled unit including the carbon block filter 20, the pressurevessel 28 and the quick-disconnect 30. Similarly, as hereinafterdescribed, a radiant energy monitor is provided for monitoring theperformance of the UV discharge bulb 21 and providing an audio and/orvisual indication of when the discharge bulb 21 has malfunctioned. Asource quick-disconnect is provided at 32, which operates with a powerinterlock hereinafter described, so that the UV discharge bulb 21 can beeasily and safely withdrawn from the unit when the shroud 24 is raised.

With particular reference now to FIG. 4, it is illustrated that theshroud 24 is pivotally mounted on the base 22 with a hinge 34. The hinge34 is glued, welded or otherwise suitably secured to a boss 35 disposedon the bottom edge 36 of the shroud 24. The hinge 34 engages aperturesat 37 which are molded into the base 22. The shroud 24 is thus raised bypivoting the shroud forward in the direction of the arrows 39 (FIGS. 4and 5) to expose the two major subassemblies which are intended to beserviced by the user, namely, the filter cartridge and UV dischargebulb.

UV discharge bulbs require a ballast circuit for applying a startingvoltage to the bulb and then applying a sustaining voltage to the bulb.This ballast circuit can present a danger of electrical shock or injuryto an inexperienced homeowner that is required to access the interior ofthe unit for the purpose of changing the discharge bulb. For example,with reference to the other figures and in particular to FIG. 2, it isillustrated that the UV discharge bulb 21 contains on one end thereof aplurality of electrical contacts 40 which are engaged by an electricalplug 41.

It should also be understood that the water treatment system unit 10 isnormally used on a kitchen countertop where water is often present andthere are ground fault discharge paths to plumbing fixtures, sinks, etc.To prevent the possibility of electric shock or discharge, the watertreatment system of the present invention is provided with interlockswitches, best illustrated at 45 in FIG. 7, for automaticallydisconnecting the source of radiant energy from a power supply when theshroud 24 is pivoted forward from the base 22 to access the filter andthe source. More particularly, with specific reference to FIGS. 4 and 7,the forward edge 46 of the boss 35 disposed on the shroud 24 acts as acam surface which engages forward facing actuators 49 on the interlockswitches 45. The interlock switches 45 are disposed on a board which isreceived in a frame 50, also illustrated in FIG. 8, that is formed on amolded bracket 51 that also receives a source pressure vessel 52 to fixthe same within the base 22 with the switches 45 forward facing forengagement with the forward edge 46 of the boss 35 on the shroud 24.

With reference now again to FIGS. 2 and 3, and with additional referenceto FIGS. 10, 11 and 12, it is illustrated that the filter 20 is disposedwithin a polymeric disposable pressure vessel 28 which includes aquick-disconnect or bayonet coupling at 30. The pressure vessel 28 isprovided with a generally cylindrical cross section having a sphericalend 55 which reduces stress concentrations in the pressure vessel thatcan lead to fatigue stress cracking and potentially dangerous waterleakage in the presence of the electrical subassemblies and power supplywhich are associated with the radiation source and monitors. Theopposite end of the generally cylindrical pressure vessel 28 is formedfrom a circular end cap 56 which is glued, welded or otherwise sealed toa circular end 57 of the cylindrical pressure vessel 28. An end weldseal 59, illustrated only in FIG. 3, is disposed therebetween. The endcap 56 is molded from a polymeric material and includes a water filterinlet at 60 and a water filter outlet at 61. Balls 62 and 63 cooperatewith sealing surfaces formed in the molded end cap 56 to provide aninlet check valve and an outlet check valve, respectively. The inlet andoutlet check values automatically trap water and contaminants within thefilter pressure vessel 28 when the filter cartridge or unit is removedor replaced by the user. This prevents the user from being exposed toany contaminants which have built up on the exterior of the carbon blockfilter 20 disposed therein and prevents water from being spilled withinthe shroud or base of the unit which contains electrical components.

With specific reference to FIGS. 3 and 12, the bayonet coupling 30comprises a plurality of radial tangs 65 which are disposed on the endcap 56 of the pressure vessel 28. The tangs 65 are captured in aplurality of apertures 66 which are disposed in the base 22. When theuser is provided with an indication that the filter cartridge must bereplaced, the user need only pivot the shroud 24 forward to reveal thecylindrical pressure vessel 28. The user then grasps the pressurevessel, turns the pressure vessel approximately 45° counterclockwise toremove the tangs 65 from the apertures 66 and withdraws the filtercartridge from the water treatment unit. When replacing the water filtercartridge, the user need only align the water filter outlet 61 with anoutlet port 68, best illustrated in FIG. 3, disposed in the base 22.Once the water filter outlet 61 is inserted in the port 68, the filtercartridge need only be rotated clockwise until resistance is felt andthe tangs 65 are embedded in the apertures 66 in the base 22.

With specific reference to FIGS. 2, 3 and 12, the carbon block filter 20is mounted within the pressure vessel 28 on the end cap 56 with athreaded connector 70 which communicates with the interior of the carbonfilter 20 and is glued, welded or otherwise suitable secured in the endcap 56. The threaded connector 70 provides a fluid connection betweenthe interior of the carbon block filter 20 and the water filter exit 61.A compressible, resilient elastomer seal 71, best illustrated in FIG. 3,is captured between the carbon filter 20 and the threaded connector 70to provide a seal that prevents leakage of contaminated, untreated waterinto the filter exit 61.

With reference now to FIGS. 2, 3, 11 and 12, it is illustrated that thefilter cartridge 28 of the water treatment system is provided withelastomeric sliding water inlet and water outlet seals whichautomatically provide fluid connections with the base 22. With specificreference now to FIGS. 11 and 3, it is illustrated that the water filteroutlet 61 is molded into the end cap 56 with a pair of annular shouldersat 72 which capture an elastomeric, resilient sealing O-ring at 73. TheO-ring 73 automatically engages the cylindrical sidewalls of the port 68in the base 22 when the water filter outlet 61 is inserted in the port68 to provide a fluid connection between the base 22 and the waterfilter cartridge 28.

With reference now to FIGS. 2, 3, 10 and 11, the water filter inlet,formed at 60 in the end cap 56, introduces water to the interior of thewater filter pressure vessel 28 at a point which is radially displacedfrom the interior of the carbon filter 20 and the water filter outlet61. This introduces water to the exterior of the water filter 20establishing a radially inward flow path which results in superiorfilter performance. The sliding water inlet seal for the water inlet 60is formed with an elastomeric, torroidal seal 75, best illustrated inFIG. 10, which is mounted in a water inlet port 78 disposed within thebase 22. A compression coil spring 79 is captured between the torroidalseal 75 and a shoulder disposed in the inlet port 78. The top surface 80of the torroidal seal 75 is thus spring-biased upwardly into engagementwith the flat, bottom surface 81 of the end cap 56 of the cylindricalpressure vessel 28 to establish a sliding seal with the filtercartridge. The tangs 65 on the end cap 56 and the apertures 66 in thebase 22 are provided with a geometry which automatically registers thewater filter inlet 60 in the filter cartridge with the inlet port 78 inthe base 22 when the tangs are rotated so that they are fully embeddedin the apertures 66. This automatically registers the water filter inlet60 with a seal inlet port 82 in the torroidal seal 75 to provide for theintroduction of water to the filter cartridge. The torroidal seal 75 isalso provided with an annular lip 83 which is biased outwardly intosliding engagement with the cylindrical walls of the inlet port 78 inthe base 22 for sealing water therein. The design of the water filtercartridge is disclosed in further detail in co-pending application Ser.No. 08/017,773, filed Feb. 16, 1993, now U.S. Pat. No. 5,344,558, andentitled WATER FILTER CARTRIDGE. The disclosures of this related patentapplication are hereby incorporated by reference.

In this preferred embodiment, the carbon block filter 20 is constructedaccording to the teachings of prior U.S. Pat. Nos. 4,753,728, 4,859,386and 5,017,318. The disclosures of these prior patents are herebyincorporated by reference. Preferably, the filter 20 comprises a pressedcarbon block formed from a carbon having a narrow pore-size distributionwith a substantial percentage of the pore sizes in the micropore range.As used herein, the micropore range includes pores having a diameter ofapproximately 10 microns or smaller. The carbon block 20 may be providedwith a carbon density that varies radially with the carbon being packedless densely near the surface of the block and more densely near theinterior of the block. That is to say, the block may be provided with aradially variable density, the density increasing toward the interior ofthe block. This and the provision of a multi-layer scrim or screenoverwrap 85 (FIG. 2) captures larger particulates on the outside of thecarbon block filter to prevent masking of the carbon pores by largerparticulates and thus increasing the useful lifespan of the filterblock. The radially inward flow path also substantially increases theability of the brittle pressed carbon block to withstand water pressure.It should be readily understood that any fracturing of the carbon blockimmediately creates water channels which defeat the filter and result incontaminant breakthrough. The carbon block is pressed with a bindercomprising a low-melt index polymeric material having a melt index ofless than one gram per ten minutes as determined by ASTM D1238 at 190°C. and 15 kilograms load whereby the polymer binder material tackifiesat elevated temperatures without becoming sufficient liquid tosubstantially wet the carbon particles and mask the pores of the carbonwhich effectively reduces or eliminates the effective carbon surface.Forming the carbon block filter 20 with such a high molecular weight,low-melt index polymeric binder, and with the other features describedherein and in the aforesaid patents, is considered essential to theperformance of the radiation source which receives filtered water fromthe filter 20 because if any significant amount of contaminants orparticulates defeat the filter 20, these contaminants or particulatescan mask microorganisms from killing radiation.

With reference again to FIG. 2, and now also to FIG. 13, it isillustrated that the water treatment system 10 of the present inventioncomprises an elongate source pressure vessel 52 disposed in the base 22with an elongate ultraviolet discharge bulb or lamp 21 disposed therein.The lamp 21 is disposed within a glass quartz tube 90 which alsocontains conductors 91 which are connected to electrical contacts 40.The glass quartz tube 90 is rotatably mounted in a compression nut 92which is received on the threaded neck 93 of the generally bottle-shapedcylindrical source pressure vessel 52. An O-ring seal 94 is trappedbetween the compression nut 92 and inwardly facing annular slopedsurface 95 on the neck 93 of the bottle-shaped source pressure vessel 52and the exterior cylindrical surface of the quartz glass tube 90,providing a sealing relationship between these members. A spring clip orthreaded cap at 96 engages the end insulator 97 of the lamp 21 torotatably mount the lamp 21 on the compression nut 92. The compressionnut 92 includes a plurality of finger or hand-holds 98, best illustratedin FIG. 2, so that the compression nut 92 acts like a twist-off threadedbottle cap disposed on the top of the bottle-shaped source pressurevessel 52 with the O-ring 94 acting as a sliding elastomeric seal whichautomatically seals the top of the bottle-shaped pressure vessel.

With continued reference to FIGS. 2 and 13, upon receiving an audio orvisual indication that the lamp 21 has malfunctioned, the user need onlypivot the shroud 24 forward to reveal the compression nut 92 of thesource quick-disconnect 32. The interlock switches heretofore describedautomatically disconnect electrical power supplied to the ballast powersupply circuit and the lamp 21 so that the user can safely grasp theelectrical plug 41 to disengage the same from the electrical contacts 40extending from the top of the lamp 21. Thereafter, the user need simplygrasp the compression nut 92 and twist the same counterclockwise untilthe threads are released and the lamp 21 and quartz tube 90 can bewithdrawn as a unit from the top of bottle-shaped pressure vessel 52.The radiation source is replaced as an entire unit by inserting a newquartz tube and lamp with O-ring seal and compression nut attachedthereto into the neck 93 of the bottle-shaped pressure vessel 52 andthen turning the compression nut counterclockwise until it is firmlyseated and in sealing engagement with the neck of the source pressurevessel. The electrical plug 41 is then reattached to the electricalconnectors 40 extending from the top of the lamp 21 and the shroud 24 ispivoted forward to close the unit and resume normal operation.

With specific reference now to FIGS. 13 and 14, it is illustrated thatthe source pressure vessel 52 further comprises a diverter, generallyillustrated at 100, for establishing a plug flow about the elongateultraviolet discharge lamp 21. The diverter 100 is associated with thesource pressure vessel inlet 101 which is disposed on one end 102 of theelongate pressure vessel 52. The end 102 of the pressure vessel 52 isdisposed distally or opposite of the neck 93 or other end of thepressure vessel 52 where the source pressure vessel outlet 104 isdisposed. The source pressure vessel 52, the diverter 100, sourcepressure vessel inlet 101 and source pressure vessel outlet 104 areformed from stainless steel and are welded together. Stainless steel isthe preferred material to withstand the water pressure and the radiationemanating from ultraviolet lamp 21. This steel structure is also opaqueto provide a high level of protection for the remainder of the systemwhich includes components which degrade when subjected to UV radiationand to protect the user's skin and eyes. The diverter 100 comprises aradial baffle 105 containing a central aperture 106 through which thequartz tube 90 and the lamp 21 extend. A circular array of apertures 107are provided for controlling the flow of water from the source pressurevessel inlet 101 to the interior of the elongate bottle-shaped pressurevessel 52.

With continued reference to FIGS. 13 and 14, the inlet tube 101 of thesource pressure vessel abuts a diverter plate 108. The tube 101 isprovided with an outlet aperture 110 disposed on one side of the tubeand inside of the source pressure vessel 52. Water entering the sourcepressure vessel through the inlet tube 101 thus exits the aperture 110inside of the pressure vessel and is directed in a tangential path bythe plate 108. This tangential entry is generally illustrated by thearrows 111 in both FIGS. 13 and 14. The radial baffle 105 prevents anysubstantial mixing or turbulence in the water and creates a plug-likespiral flow condition illustrated by the arrows 112 in FIG. 13. Thisplug-like spiral flow condition is important to the operation of thewater treatment system as a water purifier because it prevents turnoveror mixing of the water inside of the pressure vessel 52 in a way thatpermits microorganisms to be quickly and accidently ejected from theopposite end of the source pressure vessel 52 through source pressurevessel exit tube 104 without receiving a killing dose of radiation. Thislaminar plug-like spiral flow condition not only ensures adequatecontact time between the radiation emanating from the ultraviolet lamp21 and any microorganism, but it also turns the microorganism, or anyparticulate upon which the microorganism is carried, to be sure that themicroorganism is properly exposed to killing radiation. This turningmotion may also be useful to expose any area of the microorganism thatis particularly sensitive to UV radiation.

It must be understood that this means for providing a plug flow aboutthe elongate ultraviolet discharge lamp 21 may take other embodiments.For example, a spiral glass or polymeric tube may be used to channelwater in a spiral path from a water inlet disposed at 101 to a wateroutlet disposed at 104 at the opposite end of the elongate lamp 21. Infact, it has been found that Teflon® tubing coiled about the lamp in aspiral pattern can be provided with a sufficient wall thickness towithstand water line pressures while having adequate ultraviolettransmissibility to achieve excellent kill rates. Thus, the means forproviding a plug flow about the elongate ultraviolet discharge lamp mayembody a number of alternative structures. The design of the radiationsource pressure vessel and the ultraviolet lamp is the subject ofrelated patent application Ser. No. 08/016,140, filed Feb. 10, 1993, nowU.S. Pat. No. 5,393,419, entitled ULTRAVIOLET LAMP ASSEMBLY FOR WATERPURIFICATION and the disclosures of this related application are herebyincorporated by reference.

With reference now again to FIG. 1, it is illustrated that the watertreatment system 10 of the present invention further comprises thediverter valve illustrated at 15. The diverter valve 15 is particularlyadapted for mounting on the water outlet of a household water faucet 14.Although it should be understood that it is possible to use the watertreatment system unit 10 without the diverter valve by connecting thesystem to a dedicated drinking or cooking water faucet. It is assumed,however, that in most homes only a single water faucet is available bothfor cleaning and drinking water and, thus, a diverter valve which allowsthe use of unpurified water for cleaning purposes is desirable. Adiverter valve particularly adapted for use with the water treatmentsystem of the present invention is disclosed in related patentapplication Ser. No. 07/977,161, filed Nov. 16, 1992, now U.S. Pat. No.5,279,329, entitled FAUCET DIVERTER VALVE and the disclosures of thisrelated application are hereby incorporated by reference. The ornamentaldesign of this diverter valve is also the subject of patent applicationSer. No. 07/930,182, filed Aug. 17, 1992, now U.S. Pat. No. Des. 348,722entitled FAUCET DIVERTER VALVE. The disclosures of this designapplication are also incorporated herewith by reference.

With reference now to FIG. 15, it is illustrated that in the preferredembodiment of the water treatment system of the present invention, thebody of the diverter valve 15 (or an inlet port on the base 22) includesan untreated water outlet port 115 that includes a regulator 116 forregulating the flow of water through the water treatment system 10 undervariable line pressure conditions. In the preferred embodiment, theregulator comprises an elastomeric grommet 116, the elastomeric grommethaving a central opening or restriction port 117 through which waterflows into a passage 118 that is connected to one of the two tubingpairs 16 that directs water from the faucet 14 to the water treatmentsystem 10. The elastomeric grommet 116 is seated in an annular socket120 which is normally formed on the body of the diverter valve 15surrounding the untreated water exit port 115. The grommet 116 isencapsulated by fitting 121 which encompasses the annular socket 120 andis either glued or suitable welded thereto. The fitting 121 includes aspade-shaped tubing connector 122 which is pressed into the insidediameter of one of the two tubes 16 to direct water to the watertreatment system 10.

With continued reference to FIG. 15, the port 117 in elastomeric grommet116 presents a flow restriction for untreated water exiting the port 115and entering the water treatment system 10. As line pressure increases,flow resistance through the port 117 in the grommet 116 increases andthe pressure drop across the elastomeric grommet increases. This causesthe elastomeric grommet to elastically deform, rotating a rounded edge125 of the grommet 116 inwardly in the direction of the arrows 126 toact as an iris which automatically chokes flow to the water treatmentsystem 10 as line pressure increases. As line pressure decreases, thepressure drop across the elastomeric grommet decreases and theelastomeric grommet relaxes allowing a corresponding proportionalincrease in flow. This flow regulator is important to prevent water fromjetting through the water treatment system in the event that the systemencounters unreasonably high line pressures, reducing noise in the watertreatment system and insulating the water treatment system from sharppressure increases which could lead to premature and potentiallycatastrophic failure of components within the water treatment systemwhich are subjected to line pressure. Still further, this flow regulatorenhances microbiological kill rates by controlling the rate of flowthrough the ultraviolet radiation source to provide good contact timebetween the microorganisms and the source of UV radiation and thusensure excellent kill rates. Flow regulating grommets of the typedisclosed herein are known in the industrial arts and are commerciallyavailable.

With reference again to FIGS. 5 and 6, it is illustrated that the watertreatment system 10 of the present invention is provided with a basewater inlet 130 and a base water outlet 131 in the bottom of the base22. Each of the base water inlet and outlet is provided with a 90° elbow132 and 133, respectively, which is rotatably mounted in the inlet andoutlet ports 130 and 131 in the bottom of the base 22. The flexibleinlet and outlet tubes at 16 are connected thereto so that the watertreatment system unit 10 can be mounted on either of the left or theright side of a point of use water source such as a sink countertop.This is accomplished by rotating the elbows 132 and 133 to provide forthe exit of the flexible tubes 16 from one or the other side of thewater treatment system unit 10. Channel 135 is molded on the bottomsurface of the base 22 to provide or ensure adequate clearance for theflexible tubes 16 from either the right or left sides of the unit 10.For example, in FIG. 5 the tubes 16 are illustrated exiting theunderside of the unit 10 at 136.

In FIGS. 1 and 9 it is illustrated that an appliance leakage currentinterrupter 140 is supplied on the power cord for the water treatmentsystem unit 10 for automatically disconnecting the ballast circuit andsource of radiant energy contained within the water treatment system 10from the home power supply when an electrical leakage path is present inthe water treatment system. Such appliance leakage control interruptersare known in the art and are commercially available.

With reference now to FIG. 16, a UV bulb intensity control circuit forthe water treatment system of the present invention is generallyillustrated at 150. Two considerations factor into the intensity controlof the UV lamp schematically illustrated at 21. First, it is desirableto operate the lamp 21 at maximum intensity to achieve the maximum killrate whenever water is flowing through the water treatment unit.Secondly, it is desirable to reduce the UV light intensity wheneverwater stops to prevent excessive warming of the water stagnated withinthe unit. Another problem associated with thermal soaking of the unit isthat when the temperature of the lamp 21 is allowed to increase there isa corresponding decrease in the UV output of the lamp. Thus, it is mostdesirable to have the UV lamp 21 dwell at a lower power setting (stillhigh enough to sustain UV discharge) when no water is being drawnthrough the unit so that the bulb will operate at a lower temperaturewhen full power is applied to the bulb to supply a high UV output whenwater is drawn through the unit.

A power connection to a household power source is schematicallyillustrated at 151 and an inductive ballast is illustrated at 154. Astarter circuit of a type well-known in the art is schematicallyillustrated at 158. An intensity control circuit is provided whichcomprises an RC circuit including resistance 163 and capacitance 164connected in parallel with the lamp 21 and a normally open relay 165.The normally open relay 165 is controlled by a flow switch containedwithin the water treatment system so that the relay switch 165 isnormally open when water is flowing in the unit. Thus, when water isflowing in the water treatment system, the power circuit comprisingelements 151 and 154 operate in a conventional fashion to provide fullintensity to the UV lamp 21. However, when the relay switch 165 isclosed, current is shunted through parallel RC circuit elements 164 and163 to reduce bulb intensity. This circuit is disclosed in furtherdetail in related patent application Ser. No. 08/016,594, filed Feb. 11,1993, now U.S. Pat. No. 5,324,423, entitled UV BULB INTENSITY CONTROLFOR WATER TREATMENT SYSTEM and the disclosures of this relatedapplication are hereby incorporated by reference.

With reference now to FIG. 17, a circuit is generally illustrated at 170for monitoring the status of the UV lamp 21. Clearly, the effectivenessof radiation in the killing of a microorganism depends upon the statusof the UV bulb 21. The bulb may not operate properly for a variety ofreasons. For example, the bulb may burn out, break or power to the bulbmay be interrupted. Thus, a radiation source or UV lamp monitoringcircuit is provided which includes a voltage detection circuit coupledin parallel across the bulb or lamp 21. The monitoring circuit,generally illustrated at 170, includes a means for emitting a statussignal when the voltage is undesirably high (as might be associated witha burned out or a broken bulb) or when the voltage is undesirably low(as might be associated with a short-circuit). The status of the bulb 21is indicated via status signals that are in a format compatible with aCMOS microprocessor or logic inputs. Such an arrangement enables thebulb status to be processed by a microprocessor which would thenindicate to the consumer by audio and/or visual signals the status ofthe bulb.

In FIG. 17, the components of FIG. 16 other than the lamp 21 have beenomitted for clarity. Accordingly, in FIG. 17 the lamp 21 is illustratedin conjunction only with the lamp status monitor circuit 170. Themonitor circuit 170 includes a transformer 172, a rectification circuit174 and a signal generation circuit 176. The transformer 172 is coupledin parallel with the UV lamp 21 to step down the voltage across thelamp. The transformer secondary current is rectified by the circuit 174and applied to the circuit 176. A signal is outputted in CMOS compatibleform by the circuit 176 whenever the voltage across the lamp 21 isundesirably high or undesirably low. The voltage which the lamp 21inherently seeks is referred to as the sustaining voltage. Thesustaining voltage typically is selected to be approximately one-half ofthe line voltage. Two conditions can drastically change the sustainingvoltage. First, when there is no current through the bulb there is novoltage drop across the inductor 154 (illustrated in FIG. 16) and thevoltage across the bulb 21 is the full line voltage. Second, if thestarter shorts out, the voltage across the bulb is zero.

Thus, the bulb status is monitored by detecting for these threedistinctly different voltage levels (i.e., line voltage, sustainingvoltage and zero voltage) across the bulb. Sustaining voltage indicatesthat the lamp 21 is functioning properly. Line voltage indicates thatthe bulb is burned out, broken or missing. Zero voltage indicates thatthe starter has shorted out or that power is interrupted.

With continued reference to FIG. 17, the impedance of the power supplyballast 154 (FIG. 16 only) is selected to reduce the current through theUV bulb to an ideal value for which the bulb is designed. The bulb 21 isa conventional gas discharge UV bulb including a pair of filaments 178and 179. The filaments are connected in series with the ballast 154, thebulb acting as a voltage regulator. As the impedance of the ballastincreases, the current through the bulb decreases. Any increase incurrent decreases the impedance of the bulb, thus maintaining thevoltage across the bulb at an essentially constant value. Finally, thestarter circuit 158 (FIG. 16 only) is also of a conventionalconstruction and is connected in series between the filaments 178 and179 of the lamp 21. The transformer 172 includes a primary 180 connectedin parallel across the bulb 21. The secondary 181 of the transformer iscenter tab grounded at 182. The transformer 172 therefore steps down thevoltage across the bulb 21.

With continued reference to FIG. 17, the rectification circuit 174 isconventional and includes a pair of diodes 183 and 184 electricallyconnected to opposite sides of the secondary 181. The outputs of thediodes are connected in series with a resistor 186 having groundedcapacitors 187 and 188 on either side thereof. Accordingly, a DC voltageappears at node 190 which is directly proportional to the AC voltageacross the lamp 21.

With continued reference to FIG. 17, the signal generation circuit 176generates a logic output at node 191 which can be used by amicroprocessor operating the diagnostic system. Node 190 is connectedthrough a zenner diode 192, a node 193 and a capacitor 194 to ground.The conducting voltage of the zenner diode is selected so that thevoltage generated by the rectification circuit 174 will not cause thediode to conduct when the bulb is at normal sustaining voltage. Node 190is also connected through resistor 196 and diode 199 to the supplyvoltage VCC. A battery backup 198 is connected through diode 199.Transistor 200 is series connected with resistor 202 between VCC andground. The output of the transistor 200 at node 191 is the CMOS LOGICOUT A point. Transistor 204 switches transistor 200 and, therefore,LOGIC OUT B under the control of the signal at node 193.

With continued reference to FIG. 17, when the primary of the transformer172 (i.e., the bulb voltage) goes to the line voltage (meaning the bulbis not lit or is trying to light), the zenner diode 192 turns on. Thesignal at node 193 turns on transistors 204 and 200 to provide a highlogic output at LOGIC OUT A and low logic output at LOGIC OUT B. Whenthe primary voltage of the transformer 172 goes to zero volts (meaningshorted starter or no power), current will be supplied to the circuit176 by the battery backup 198 as diode 199 will be allowed to conductbecause of the absence of the rectified supply voltage. In such case,both LOGIC OUT A and LOGIC OUT B are low. When the bulb is at sustainingvoltage (meaning bulb lit), the logic output at LOGIC OUT A is low andthe logic output at LOGIC OUT B is high.

Hence, the output at LOGIC OUT A is high if the voltage is abnormallyhigh and the output at LOGIC OUT B is low if the voltage is eitherabnormally low or abnormally high. As explained, abnormally high voltageindicates no power or a shorted starter. Abnormally low voltage means aburned out bulb, a broken bulb or a missing bulb. In any of theseevents, the consumer is notified by an audio and/or visual signal drivenby a microprocessor that receives the A and B LOGIC signals. On theother hand, if the logic output at LOGIC OUT A is low, and the logicoutput at LOGIC OUT B is high, then the bulb is operating normally.

With reference now to FIG. 18, it is illustrated that the LOGIC A and Bsignals are received by a CMOS microprocessor 220 which processes thislogic information as well as input from a magnet actuated reed switch orflow switch schematically illustrated at 272. Driver circuits actuatedby the outputs schematically illustrated at 223 are controlled by themicroprocessor 220 which processes information obtained from the logicinputs A, B and the magnetically actuated reed switch 222 to provide theconsumer with audio and/or visual information in the form of a blinkingor constantly lit LED display concerning the status of the UV lamp.LOGIC signals A and B, as hereinafter described, are directly convertedinto a lamp status LED display which indicates when any of theaforementioned lamp fault conditions is present. An audio signal, buzzeror beep may also be provided to alert the user of the lamp malfunction.

The flow switch schematically illustrated at 222 is known in the art andis preferred to be the type illustrated in U.S. Pat. No. 5,070,220,issued Dec. 3, 1991 and entitled FLOW SWITCH CONSTRUCTION, thedisclosure of which is hereby incorporated by reference. Briefly, theflow switch comprises a magnet 221 which is biased by spring 224 to aposition distal from reed switch 225. The reed switch 225 may benormally closed or normally open, but in this case is normally open sothat when water pressure is applied to the head of a piston containingmagnet 221, to displace the same in the direction of the reed switch225, the reed switch 225 is closed providing a signal to themicroprocessor 220 that flow is present in the water treatment system.This signal is then used by the microprocessor 220 to drive via output228 the normally closed relay 165 of the UV bulb intensity controlcircuit illustrated in FIG. 16.

The flow switch 222 and the microprocessor 220 also comprise the filtermonitor circuit of the present invention since the useful lifespan ofthe filter cartridge can be directly related to the total accumulatedwater flow through the water treatment system unit. Thus, whenever thereed switch 225 is closed it is assumed that water is flowing throughthe filter cartridge and a register in microprocessor 220 connected to aclock provides a measure of total accumulated flow based on the totalaccumulated time that the reed switch 225 is closed. When the totalaccumulated time reaches a predetermined set time within themicroprocessor that is associated with the end of the useful lifespan orthe end of the life of the filter cartridge, one or more of the audio orvisual drivers 223 are used to provide the consumer with an audio and/orvisual indication that the filter cartridge has been exhausted and hasreached its end of life.

With reference now to the other figures, and in particular FIGS. 7 and9, it is illustrated that the UV bulb intensity control circuitillustrated in FIG. 16, the UV lamp monitor illustrated in FIG. 17 andthe filter monitor illustrated in FIG. 16, are mounted on a main circuitboard 230 that is fastened to an interior bulkhead 231. The ballast 154is also mounted on the main circuit board. The UV pressure vesselsubassembly, which also includes the flow switch 222 and mountingbracket 51 (FIG. 8) are also received and fastened to the bottom of thebracket 231, as best illustrated in FIG. 7. The interlock switches 45are then received in frame 50 of bracket 51 and the entire assembly,including the main circuit board 230, the ballast 154 and the sourcepressure vessel subassembly are inserted into the bottom of a tower 235,best illustrated in FIG. 7. The tower 235 forms the top portion of thebase 22 along with an upstanding, cooperating back 236, best illustratedin FIGS. 4 and 9. The tower 235 and the back 236 are fastened togetherand fastened to the bottom plate 238 (best illustrated in FIGS. 4 and 9)of the base 22 to fully encapsulate all of the major electricalsubassemblies, including the UV source pressure vessel. Only thethreaded neck 93 of the UV source pressure vessel extends from the topof the tower 235 (FIG. 3).

With reference now also to FIG. 3, it is illustrated that an enunciatorboard 240, which is electrically connected to the main circuit board230, is also mounted in the top of the tower 235. The board 230 includesdriver circuits for LED display 31, an audio enunciator or buzzer 241,and pushbutton resets at 242 for resetting the monitor circuitscontained on the main circuit board 230. The LED display 31 includesthree different color LED arrays or lamps, one red letup for indicatingthe status of the ultraviolet lamp, one orange lamp to indicate thestatus of the filter, and one green lamp to indicate the operatingstatus of the water treatment system. These three different color LEDlamps are mounted in a window 245 in the tower 235 (best illustrated inFIG. 3) of the base 22. The tower 235, the LED window 245 and the shroud24 are provided with a geometry that automatically registers the threedifferent color LED lamps with three apertures 250 (best illustrated inFIGS. 5 and 6) of the shroud 24. The output signals 223, illustrated inthe schematic of the microprocessor 220 of FIG. 18, drive the audioenunciator 241 and the LED display 31 according to the logic hereinafterdescribed in the operation of the water treatment system. It should beunderstood that to program the CMOS general purpose microprocessor toprovide the logic outputs necessary to drive the buzzer and LED lamps asset forth hereinafter is well within the scope of knowledge of one ofordinary skill in the art.

Operation

The water treatment system 10 is first connected to a source of cold tapwater (drinking water) with a diverter valve, such as the oneillustrated at 15 in FIG. 1, or a dedicated cold water drinking tap notillustrated herein. The filter cartridge 28 of the unit is then insertedby pulling the front cover or shroud 24 forward in the direction of thearrows 39 in FIG. 5. Symbols provided on the exterior of the filtercartridge 28 are aligned with symbols provided on the base 22 of theunit and the water filter outlet 61 is plugged into the port 68 in thebase 22 (best illustrated in FIG. 3). While pressing on the top of thefilter cartridge 28, the user turns the cartridge clockwise until all ofthe radially-extending tangs 65 on the periphery of the filter cartridge28 are fully meshed with the apertures 66 in the base 22. These stepsare reversed to remove the filter cartridge.

The UV lamp 21 is installed by removing the compartment cap 251,illustrated in FIG. 3, and inserting the UV lamp assembly, includingquartz tube 90 and compression nut 92, into the upwardly-facing opening252 in neck 93 of the pressure vessel 52, which projects upwardly fromthe back of the tower 235 of the base 22. The UV lamp power cord and theplug 41 is then connected to the four upstanding electrical connectors40 extending from the top of the UV lamp 21. Because the UV lamp isrotatably mounted on the compression nut 92, the nut turns freely. Theuser then turns the nut in a clockwise direction until it is tight tofirmly attach the UV lamp 21 in the pressure vessel 52. The compartmentcap 251 is then replaced and the unit is plugged into a convenientsource of electrical power, such as the household electrical outletillustrated at 18 in FIG. 1. The filter monitor circuit and UV lampmonitor circuit are then initialized by pushing buttons 242 on the topof the tower 235 of the base 22. The unit is ready for operation whenthe shroud 24 is pivoted forward so that all internal components arecovered and the unit takes the configuration illustrated in FIGS. 1 and5 with the shroud closed. These steps are reversed to remove the UVlamp.

The power cord for the water treatment system unit includes an applianceleakage current interrupter (ALCI) 140, which automatically detectselectrical current leakage from the device. When anelectrically-dangerous condition arises, the ALCI automatically shutselectrical power off to the water treatment system. The procedures forsetup and re-setup of ALCI devices is well-known.

The diagnostic (filter monitor and UV lamp monitor) circuits of thewater treatment system keep the user informed on a continuous basis ofthe water treatment system's condition. The operating conditions of thewater treatment system are continuously indicated by an audioenunciator/buzzer 241 and the LED display 31 (FIG. 3). When the frontshroud 24 is closed and the power is turned on, the green LED or lamplights up, indicating that the unit is operating normally. When treatedwater is flowing through the water treatment system, the green lampblinks. When maintenance of the water treatment system is necessary, thebuzzer sounds and the red or orange LEDs signal the corrective actionrequired. One sound of the buzzer indicates that maintenance will soonbe required. When the filter or the UV lamp must be changed immediately,the buzzer sounds twice in rapid succession. Whenever the buzzer sounds,the user must check the blinking condition of the LED display todetermine the type of maintenance necessary. The microprocessor 220,illustrated in FIG. 18, is programmed to provide output signals 223 tothe buzzer and LED drivers contained on enunciator board 240, accordingto the following table, to indicate the condition of the water treatmentsystem unit and the type of maintenance required. Generally, when thegreen lamp is on, the user is free to use the water treatment systemunit. When treated water has passed through the unit and the green lampis blinking alternately with another lamp, maintenance is necessary butthe user can still continue to use the water treatment system. When thegreen lamp is out, maintenance is required immediately. In this case,the user is not to use the water treatment system. If the system horn orbuzzer beeps constantly, the unit should be unplugged immediately.Electrical problems may be present:

                                      LOGIC TABLE                                 __________________________________________________________________________    When treated water is flowing                                                                         When treated water is not flowing                             Lamp                  Lamp                                                    Red                   Red                                                     (ultraviolet                                                                        Orange                                                                            Green       (ultraviolet                                                                        Orange                                                                            Green                                 Buzzer  lamp) (filter)                                                                          (operating)                                                                         Buzzer                                                                              lamp) (filter)                                                                          (operating)                                                                         Condition                       __________________________________________________________________________    None    out   out blinking                                                                            none  out   out on    Normal operation.               One sound at                                                                          out   blinking                                                                          blinking                                                                            none  out   out cn    Usable but filter               beginning of use                              needs to be changed                                                           soon.                           One sound at                                                                          blinking                                                                            out blinking                                                                            none  out   out on    Usable but                      beginning of use                              ultraviolet lamp                                                              needs to be changed                                                           soon.                           One sound at                                                                          blinking                                                                            blinking                                                                          blinking                                                                            none  out   out on    Usable but filter               beginning of use                              and ultraviolet lamp                                                          need to be changed                                                            soon.                           Sounds while                                                                          out   blinking                                                                          out   none  out   blinking                                                                          out   Unusable.                       water is flowing                              Neccesary to                                                                  change the filter                                                             lmmediately..sup.1              Sounds while                                                                          blinking                                                                            out out   none  blinking                                                                            out out   Unusable.                       water is flowing                              Ultraviolet lamp                                                              needs to be changed                                                           immediately..sup.2              Sounds while                                                                          blinking                                                                            blinking                                                                          out   none  blinking                                                                            blinking                                                                          out   Unusable. Filter                water is flowing                              and ultraviolet lamp                                                          need to be changed                                                            immediately..sup.1 2            Sounds  blinking                                                                            out or                                                                            out   sounds                                                                              blinking                                                                            out or                                                                            out   The ultraviolet lamp            continuously  blinking  continuously                                                                              blinking  is not operating.                                                             Change it. If the                                                             same condition                                                                persists even after                                                           putting in a new                                                              lamp, do not use                                                              the unit and cut the                                                          power immediately.              __________________________________________________________________________     .sup.1 After changing the filter, reset the filter moniter.                   .sup.2 After changing the ultraviolet UV lamp, reset the UV lamp moniter.

The above description should be considered exemplary and that of thepreferred embodiment only. It should be understood that modificationswill occur to those who make and use the invention. The true scope andspirit of the present invention should be determined with reference tothe appended claims and it is desired to include within the presentinvention all such modifications that come within the proper scope ofthe claims.

We claim:
 1. A point of use water treatment system for home usecomprising:a pressed carbon block filter for removing particulates andorganic contaminants from water, said filter including a filter waterinlet and a filter water outlet; and a source of radiant ultravioletenergy for receiving water from said filter and killing microorganismsin said water, said source of radiant energy comprising:(i) an elongateultraviolet discharge lamp having an elongate central axis defining anaxial direction; (ii) a vessel defining an open chamber around saidelongate ultraviolet discharge lamp, said vessel containing water flowthrough said source of radiant energy, said vessel including a sourcewater inlet and a source water outlet, said source water inlet receivingwater from said filter water outlet; and (iii) directional meansproximate said source water inlet for establishing plug-like spiral flowwithin said open chamber with a substantial axial and tangentialcomponent about said elongate ultraviolet discharge lamp, said flowextending between said source water inlet and said source water outlet;whereby filtration, water flow, water quality and microbiological killrates are enhanced.
 2. A point of use water treatment system for homeuse as claimed in claim 1, further comprising:flow regulator means forautomatically regulating water flow through the water treatment systemunder varying water source pressures.
 3. A point of use water treatmentsystem for home use as claimed in claim 1 further comprising:filtermonitoring means for monitoring the amount of water flowing through thefilter and providing an indication to a user when the filter has reachedend-of-life.
 4. A point of use water treatment system for home use asclaimed in claim 3, further comprising:filter quick-disconnect means forallowing the user to quickly and easily change said filter in responseto an indication from said filter monitoring means.
 5. A point of usewater treatment system for home use as claimed in claim 1, furthercomprising:radiant energy monitor means for monitoring performance ofsaid energy source and providing an indication when said energy sourcehas reached end-of-life.
 6. A point of use water treatment system forhome use as claimed in claim 5, further comprising:sourcequick-disconnect means for providing a user with the ability to changesaid energy source in response to an indication from said radiant energymonitor means.
 7. A point of use water treatment system for home use asclaimed in claim 1, wherein said filter includes:a central axis; anactivated carbon having a narrow pore size distribution with asubstantial number of pores that are 10 microns in diameter and less; ahigh molecular weight low melt index polymeric binder which minimizesmasking of said activated carbon; and a radially inward flow pathextending between said filter water inlet radially distal from saidcentral axis and said filter water outlet located near said centralaxis.
 8. A point of use water treatment system for home use comprising:apressed carbon block filter for removing particulates and organiccontaminants from water, said filter including a central axis andcomprising:(i) an activated carbon having a narrow pore sizedistribution with a substantial number of pores that are 10 microns indiameter and less; (ii) a high molecular weight low melt index polymericbinder which minimizes masking of said activated carbon; and (iii) aradially inward flow path extending between a filter water inletradially distal from said central axis and a filter water outlet locatednear said central axis; a source of radiant ultraviolet energy forreceiving water from said filter and killing microorganisms in saidwater, said source of radiant energy comprising:(i) an elongateultraviolet discharge lamp having an elongate central axis defining anaxial direction; and (ii) means for establishing plug-like spiral flowwith a substantial axial and tangential component about said elongateultraviolet discharge lamp between a source water inlet and a sourcewater outlet, said source water inlet receiving water from said filterwater outlet; flow regulator means for regulating water flow through thewater treatment system under varying water source pressures; filtermonitoring means for monitoring the amount of water flowing through thefilter and providing an indication to a user when the filter has reachedend-of-life; filter quick-disconnect means for allowing the user toquickly and easily change said filter in response to an indication fromsaid filter monitoring means; and means for automatically reducing powersupplied to said energy source in response to a signal from said filtermonitoring means; whereby filtration is optimized, ample water flow isprovided, water quality is maximized and microbiological kill rates areenhanced.